Of 1,949 successive acute severe head injuries (SHI) over a period of 11 years 1999-2009, 613 (31.5%) underwent evacuation of mass lesions. Mortality at 3 months of evacuated mass (EM) lesions was higher over 10 years compared with that of non-EM lesions (it was overall 22%). The reduction of mortality was significantly less in EM compared with that for non-surgical cases (14.4-9.4% recently) and for the cases that were operated but not for mass evacuation (18.1-12.1%). A few explanations are: first, more SDH (60.5% of the EM recently compared with 45.9% in the first few years); second, more severe cases and older patients with co-morbidities were treated surgically; third, advances in prehospital care brought more severe patients to operative care - the rate of referrals decreased from 61.5% to 52.8% recently; fourth, part of the significant shortening of the injury to NT admission time (163-141 min) vanished owing to the parallel elongation of admission to operation time (95-100 min), thus, the threshold recommendation of 4 h to mass evacuation was achieved in only 52%; fifth, introducing decompressive craniectomy was not associated with outcome improvement.